問題文
An application serves users in three continents and needs low latency reads near each of them, with data partitioned by customer. Which design does this point to?
選択肢
- Three independent databases with an application layer that routes by customer, and a nightly job that copies the reference tables between all three.
- A cache cluster in each region in front of one central database, because a cache removes the latency of the cross-region round trip for both reads and writes and therefore satisfies the requirement without changing the database design.
- A distributed database whose shards are placed in different regions, so that data for each set of key values sits close to its users.
- A single database with read replicas in each region.